Infrared (IR) thermometers have been used to measure body temperature. Human IR temperature measurements are typically made by placing an IR detector in the vicinity of a person's ear canal, also known as the auditory canal. Generally such IR thermometers include a tapered conical probe section situated over or adjacent to an IR detector for ease of placement of the tip of the thermometer probe into the opening of a person's auditory canal.
The most accurate representation of the temperature of the human body has been found to be presented by the surface of the ear drum, the tympanic membrane. The temperature at various other locations on the surface of the auditory canal fall off moving away from the tympanic membrane. The temperature readings are typically the lowest at the walls of the auditory canal, particularly at the walls of the auditory canal outside of the skull wall and towards the auricle, the outer exposed surface of the ear.
The tapered conical section probe and the IR sensor can define a sensitive measurement axis substantially through the center of the tapered conical section. The problem is that to achieve a most accurate temperature measurement, the IR detector and the sensitive measurement axis should be properly aligned for an optimal view of the tympanic membrane while reading only a minimal IR contribution from the wall of the ear canal.
In one solution described in U.S. Pat. No. 6,631,287, commonly owned by the assignee of the present invention, the Welch Allyn Corporation of Skaneateles Falls, N.Y., the hottest temperature in a field of view of an IR sensor array was located in order to assist in positioning an IR probe. While there are merits to this approach, it might not always be the case that the hottest temperature in any given field of view gives the best placement of the IR probe in the auditory canal for a most optimal view of the tympanic membrane.
What is needed is an IR probe orientation system and method that can guide a user of an IR thermometer to achieve a physical positioning of an IR probe in an auditory canal for an optimized field of view of the tympanic membrane.